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Surface Mounted Thermostat.
Operation Testing (not including 600V models)
Water In Tank Is Cold With Power ON.
1. This procedure assumes line voltage, ECO and
elements are in working order.
2. TURN OFF POWER TO WATER HEATER.
3. Remove access cover from lower control box.
Remove insulation from inside of control box.
Remove plastic cover from thermostat.
4. Turn power "ON" to water heater.
5. Set multi-meter to "Volts AC".
6. Check across terminals L1 & L3 of thermostat
(see illustration 8)
A) Rated voltage NOT present,
Check fuses and or line voltage.
B) Rated voltage IS present,
proceed to next step.
7. Check across terminals L4 and T2 of thermostat (see illustration 9).
A) Rated voltage NOT present, Recheck ECO. If ECO is okay, replace thermostat.
B) Rated voltage IS present, okay, thermostat is calling for heat, go to next step.
8. Check across element terminals (see illustration 10).
A) Rated voltage NOT present, check wire connections from thermostat to element.
B) Rated voltage IS present, Repeat element testing, see page 15.
Water Temperature In Tank Is Above Thermostat Setting.
1. This procedure assumes line voltage, ECO and
elements are in working order.
2. Turn power "ON" to water heater.
3. Set multi-meter to "Volts AC".
4. See illustration 9 above, check across terminals L4 and T2 of thermostat.
A) Rated voltage IS present, replace thermostat.
B) Rated voltage NOT present, thermostat is okay.
C) Lower than rated voltage IS present, recheck for grounded element
(see page 15).
SERVICE PROCEDURE MCE-VII
High voltage exposure. To avoid hazard to
life or property, use extreme caution when
making voltage checks .
Illustration 8
Page 21
Thermostat Testing
DANGER
Illustration 9
Illustration 10
21
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